Rhosghobel is mentioned as one of several specific locations. Perhaps they were borrowing sugar at each of those instead.

The purpose of the scouting is made perfectly plain in the following paragraph.

They stopped at Rhosghobel. Radagast wasn't there. The rest is supposition.

LR

It is also made plain in that same paragraph that the scouts are consulting with other allies (such as the Eagles). Radagast falls under the same umbrella. "Good and ill have not changed since yesteryear; nor are they one thing among Elves and Dwarves and another among Men. It is a man's part to discern them, as much in the Golden Wood as in his own house." - Aragorn